Molded magnetic rolls



569% 1964 c. w. AURlcH ETAL MOLDED MAGNETIC RoLLs Filed March 28, 1962ff/W United States Patent O 3,149,403 MOLDED MAGNETIC ROLLS Christoph W.Aurich and Edward A. Bragg, Clemson, S.C., assignors, by mesneassignments, to Maremont Corporation, Chicago, Ill., a corporation ofIllinois Fiied Mar. 28, 1962, Ser. No. 183,167 6 Claims. (Cl. 29-1295)This invention relates to drafting devices of the type used in textilemachines and more particularly to magnetic drafting elements having anovel plastic-type housing.

Magnetic drafting rolls for use in textile machines, such as spinningand roving frames and the like, have recently gained great commercialacceptance. The reason for this acceptance is that they have eliminatedthe necessity of using complicated and cumbersome weighting devices toassure adequate gripping of a sliver passing between top and bottomrolls.

Heretofore, magnetic top rolls have comprised a plurality of elementsmanufactured independently of each other. Thus, a typical roll wouldhave a cylindrical magnet, a hollow sleeve portion to house the magnet,pole pieces, pole piece extensions, and gudgeons. Typically rubber cotsof uniform thickness are provided to tit on a reduced portion of thesleeve. Because of the necessity of assuring even pressure of the rollson the sliver each element of the roll necessarily was carefullymachined to provide concentricity of the pieces. Moreover, a grindingoperation was necessary after the final assembly to further insureconcentricity. With the exception of the cots each piece would be ofstrong metal. As can well be imagined, such a construction was extremelyexpensive.

It is to these problems that the present invention addresses itself. Themajor object of this invention is to provide a magnetic top roll, ofextremely simple construction, which has built-in concentricity withoutthe necessity of machining.

In general, this present invention comprises a permanent magnet andpermanently aiiixed or integrally formed pole pieces embedded in amolded plastic shell.

Other features, objects, and advantages of the present invention will beapparent to those skilled in the art from the following detaileddescription thereof and the accompanying drawings, wherein:

FIG. l is a side elevation in section of one embodiment of theinvention;

FIG. 2 is a view of FIG. 1 taken along the line 2-2; and

FIGS. 3 and 4 are views similar to FIG. l of alternative embodiments ofthe invention.

In referring to the drawings and more particularly to the constructionshown therein of the end portions of the rolls only one end will bedescribed as the opposite end of each embodiment is identical thereto.

In the drawings are shown several embodiments of this invention. It willbe there noted that a cylindrical permanent magnet is provided. A polepiece 12 is provided which is permanently afxed to the magnet 10 as isin FIG. 1 by means of solder or other such means, or which is anintegrally formed ange portion of the magnet 10 as in FIGS. 3 and 4, andwhich has a larger diameter than that of the center portion or body ofthe magnet 10. A plastic, nonmagnetic material is provided as a shellabout the circumference of the magnet 10 at 14 leaving the pole piecesexposed however on their circumferential surfaces. Plastic 16 also isprovided at the end portions of the magnet of a reduced diameterrelative to that of the pole pieces 12. Cots 18 of rubber or the like,of uniform thickness, are mounted on the platsic end portions 16 andextend radially outward farther than the pole pieces 12.

3,149,493 Patented Sept. 22, 1964 "ice Where the magnet 10 is solid asin FIG. 1 an extension 11 is provided on the pole piece 12, of anirregular configuration, adapted to be grasped by the plastic endportion 16, and thus to maintain in predetermined position said endportion. Where, however, the magnet 10 has a hollow portion, as in FIGS.3 and 4, extending therethrough, a plastic core 17 is formed thereinwhich maintains the end portion 16 in its predetermined position. lfgudgeons 20 are desired, they are inserted in the end portion 16 as inFIG. 4.

To construct such a roll, the pole pieces and magnet are firstassembled, if they are separate. The nished magnet and pole pieces arethen inserted into a mold having locating dimensions corresponding tothe diameter of the pole pieces and the length between the outer radialsurfaces of the pole pieces. If gudgeons are to be provided, they arealso aligned in the mold. The plastic material is then injected into themold. The plastic used snould have low shrinkage values to preventcracking and checking.

On removal of the roll from the mold no additional machining isnecessary. The only final assembly is to mount the cots. Where gudgeonsare used, one final grinding operation may be necessary to assureconcentricity between the gudgeons and the pole pieces. If the mold isaccurately formed, however, even this grinding operation may be deemedlargely unnecessary.

Thus this invention greatly simplifies the construction of magnetic toprolls. A plurality of elements is eliminated. A greater degree ofaccuracy is achieved in attaining concentricity of elements than washeretofore possible and several expensive grinding operations areeliminated.

It will be apparent to those skilled in the art that many modications ofthis invention may be made without departing from the true scopethereof.

What is claimed is:

l. A molded magnetic drafting element having a cylindrical permanentmagnet,

at each end of said magnet a pole piece concentric thereof andpermanently aixed thereto, said pole pieces being of equal diameter,greater than the diameter of said magnet, and each of said pole pieceshaving an exposed circumferential surface,

a shell of molded plastic material extending between said pole piecesand about the circumferential surface of said magnet thereby encasingsaid magnet,

a cylindrical end portion of molded plastic material concentric of andpermanently aixed to each of said pole pieces, said end portions beingof equal diameter and being adapted to have cots mounted thereon, and

a cot of rubber-like material of uniform thickness mounted on each ofsaid end portions, said cots being of equal thickness and having innerdiameters equal to the diameters of said end portions.

2. The element claimed in claim l wherein said pole pieces are integralportions of said magnet forming radially extending fianges thereof.

3. The element claimed in claim l wherein said pole pieces have axiallyextending portions of irregular conguration and wherein said endportions embrace said axially extending portions, said end portionsthereby being permanently aixed to said pole pieces.

4. The element `claimed in claim 1 wherein said magnet and said polepieces have a hollow portion axially extending therealong and wherein acore of said molded plastic extends through said hollow portionintegrally connecting said end portions, said end portions thereby beingpermanently aixed to said pole pieces.

5, The element claimed in claim 1 wherein a gudgeon extends outwardlyfrom each of said kend portions and wherein each said gudgeon isconcentric of said pole pieces.

6. The element claimed in `claim 1 wherein said cots have an outerdiameter which is greater than that of either said shell or said polepieces.

Referencesl Cited in the le of this patent UNITED STATES PATENTS

1. A MOLDED MAGNETIC DRAFTING ELEMENT HAVING A CYLINDRICAL PERMANENT MAGENT, AT EACH END OF SAID MAGNET A POLE CONCENTRIC THEREOF AND PERMANENTLY AFFIXED THERETO, SAID POLE PIECES BEING OF EQUAL DIAMETER, GREATER THAN THE DIAMETER OF SAID MAGNET, AND EACH OF SAID POLE PIECES HAVING AN EXPOSED CIRCUMDFERENTIAL SURFACE, A SHELL OF MOLDED PLASTIC MATERIAL EXTENDING BETWEEN SAID POLE PIECES AND ABOUT THE CIRCUMFERENTIAL SURFACE OF SAID MAGNET THEREBY ENCASING SAID MAGNET, A CYLINDRICAL END PORTION OF MOLDED PLASTIC MATERIAL CONCENTRIC OF AND PERMANENTLY AFFIXED TO EACH OF SAID POLE PIECES, SAID END PORTIONS BEING OF EQUAL DIAMETER AND BEING ADAPTED TO HAVE COTS MOUNTED THEREON, AND A COT OF RUBBER-LIKE MATERIAL OF UNIFORM THICKNESS MOUNTED ON EACH OF SAID END PORTION, SAID COTS BEING OF EQUAL THICKNESS AND HAVING INNER DIAMETERS EQUAL TO THE DIAMETERS OF SAID END PORTIONS. 